Occam’s & Hanlon’s Razors
When in doubt, cut. (But know what you’re cutting.)
Two cutting tools for trimming explanations. Prefer the one needing the fewest assumptions, and don’t blame malice for what plain incompetence already explains. Learn what each razor does, why it works, and exactly where it lies to you.
You are drowning in explanations. The website went down — was it a hacker, a bad deploy, or a cosmic ray? Your friend is an hour late — did they forget you, get hit by a bus, or just lose track of time? Every event in your life arrives with a fan of possible causes, and most of them are wrong. You need a quick way to bet on which one to chase first.
That’s what a razor is: a rule of thumb that “shaves off” unlikely explanations so you can focus on the promising ones. It isn’t a proof. It’s a prior — a smart starting bet you make before the evidence is all in. This course teaches the two most useful razors ever invented.
Occam’s razor says: among explanations that fit the facts equally well, prefer the one that requires the fewest assumptions. Hanlon’s razor says: never attribute to malice what is adequately explained by incompetence or plain carelessness. One trims complexity; the other trims paranoia. Both make you faster and less wrong — most of the time.
This course assumes you’ve met first-principles thinking and want sharper tools for the everyday job of choosing among explanations. By the end you’ll know how to count the assumptions an explanation smuggles in, why fewer assumptions really does mean fewer ways to be wrong, how Hanlon’s razor defuses your conspiracy reflex — and, crucially, the cases where each razor leads you straight off a cliff. A razor that you trust blindly stops being a tool and becomes a blindfold.
In this topic
- 1 Two Razors for a Messy World Every event arrives with a dozen possible causes, and most of them are wrong. A razor is a rule of thumb for betting on the right one first. Meet the two most useful ones ever invented — and the one rule that keeps them from backfiring. 5 min
- 2 Occam’s Razor: Cut to the Leanest Explanation Among explanations that fit the facts equally well, prefer the one that needs the fewest assumptions. What the razor really says, why it favors *simpler* not *simplest*, and why it's a tie-breaker, never a proof. 13 min
- 3 Why Fewer Assumptions Win Occam's razor isn't aesthetics — it's arithmetic. Every assumption you bolt on is another thing that has to be true, and probabilities of independent claims multiply downward. More moving parts, more ways to be wrong. 12 min
- 4 Hanlon’s Razor: Incompetence Before Malice Never attribute to malice what is adequately explained by incompetence or plain carelessness. The everyday antidote to seeing enemies where there are only tired, busy, forgetful humans. 12 min
- 5 When the Razors Lie to You A razor you trust blindly becomes a blindfold. Where Occam over-trims genuinely complex systems, where Hanlon excuses real bad actors, and how to hold both as priors you update — not verdicts you defend. 12 min
- 6 Final Exam: Occam’s & Hanlon’s Razors A graded, one-way final exam on Occam's and Hanlon's razors — counting assumptions, why fewer assumptions win, incompetence before malice, and exactly where each razor fails. Pass mark 70%. 20 min
Mark course as finished
Done with every lesson? Lock it in — your progress is saved on this device.